The HID subsystem is designed as a bus. Any I/O subsystem may provide HID
devices and register them with the HID bus. HID core then loads generic device
-drivers on top of it. The transport drivers are responsible of raw data
-transport and device setup/management. HID core is responsible of
+drivers on top of it. The transport drivers are responsible for raw data
+transport and device setup/management. HID core is responsible for
report-parsing, report interpretation and the user-space API. Device specifics
and quirks are handled by all layers depending on the quirk.
device. Once a device is registered with HID core, the callbacks provided via
this struct are used by HID core to communicate with the device.
-Transport drivers are responsible of detecting device failures and unplugging.
+Transport drivers are responsible for detecting device failures and unplugging.
HID core will operate a device as long as it is registered regardless of any
device failures. Once transport drivers detect unplug or failure events, they
must unregister the device from HID core and HID core will stop using the
channel. Any unrequested incoming or outgoing data report must be sent on
this channel and is never acknowledged by the remote side. Devices usually
send their input events on this channel. Outgoing events are normally
- not send via intr, except if high throughput is required.
+ not sent via intr, except if high throughput is required.
- Control Channel (ctrl): The ctrl channel is used for synchronous requests and
device management. Unrequested data input events must not be sent on this
channel and are normally ignored. Instead, devices only send management
payload may be blocked by the underlying transport driver if the
specification does not allow them.
- SET_REPORT: A SET_REPORT request has a report ID plus data as payload. It is
- sent from host to device and a device must update it's current report state
+ sent from host to device and a device must update its current report state
according to the given data. Any of the 3 report types can be used. However,
INPUT reports as payload might be blocked by the underlying transport driver
if the specification does not allow them.
void (*request) (struct hid_device *hdev, struct hid_report *report,
int reqtype)
- Send an HID request on the ctrl channel. "report" contains the report that
+ Send a HID request on the ctrl channel. "report" contains the report that
should be sent and "reqtype" the request type. Request-type can be
HID_REQ_SET_REPORT or HID_REQ_GET_REPORT.